HI-- I am new to this present hobby world in that I've been away from it for over 30 years. Had RC planes before and now RC scale boats.My question is: #1 Can you run a brushed motor with a brushless ESC and visa versa??

#2 The motor that I have in my scratch built 42" motorsailer is brushed and my ESC is for a brushed motor also, but it uses a battery for it and the supply to the receiver. Are there ESC'S that do not use a battery this way for brushed motors??

Brushless motors use advanced circuits to control how the motor runs, brushed just pumps electrons. You can easily find a BEC or Battery Eliminator Circuit ESC for brushed or brushless dependent on amps, I think on average higher amp units do away with BEC but I may be mistaken as I have only experience with 20 amp and lower.